Regenerative system and method of operating the same



, LZ. l QRMEQQQ @El wf m m Sw @Q h on @a n @uw 8N SQ uw 2 w HZ 0 mf. 0 E Aw o 2 m T 02m w ha 4m T VMH@ m w M1 T 6. VA E P.. Y L m .o G M B A O w N m m l, O+ n m No 5 mi A T n mv m m uw.. @NNAS m w ww Nw. uw Q Q QN .n w. m4 M w 2 w 0 w z E V n M 5 A T M z L w IW 5 G 3 m 9. a p 1. J m 4@ y 'Ilm .a 0 M A TTORNEY Patented May 21 1935 REGENERATIVE SYSTEM AND METHOD` OF OPERATING THE SAME John Allen Heany and Herbert St. Laurent, New Haven, Conn., assignors, by direct andmesne assignments, to Radio Researchl Laboratories Inc., a corporation of Delaware Applicatibn August 25, 1931, serial No. V559,214

12 Claims.

This invention relates to electrical systems for the communication of intelligence, and methods of operating the same, particularly to so-called regenerative systems, and has special reference to` the provision of methods and means in connection with tubes or cells of the type disclosed in co-pending applications of John Allen Heany and Philip M.` Haffcke, Serial No. 542,304, led June 5, 1931, and ,Serial No. 548,410, filed July 2, 1931, wherebyV the strength of incoming signals is increased within the same tube.

It is well known that if during the reception of a signal the radio frequency component of the output circuit of an electron discharge device can be reimpressed upon the input circuit in synchronism with the incoming signal, the energy of the signal will be amplified.

The fundamental principle upon which regeneration is based is the phenomenon of the reaction between two neighboring electrical circuits, and it is the function of the degree of a coupling between them.

, The principal coupling methods used for obtainingl this reaction, or regeneration, between output and input circuits are:

1. Capacitative couplings, using either the capacity of the tube itself, a separate condenser, or both in'combination.

`2. Inductive coupling Where a coil in the plate circuit and a coil in the tuned grid circuit are inductively coupled. Y k

Although it is possible to adopt, with certain modifications, either of the above mentioned coupling means to circuits including gaseous discharge devices of the referred to type, we have discovered that it is entirely unnecessary to resort to the use of the extra apparatus and circuit connections involved'in present known regenerative systems,` further, that without such apparatus andconnections it is practicalto design` and construct circuits whic are very sensitive tominute variations in the signal energy and which will amplify signals to a degree comparable favorably withthe amplification obtainable with regenerative circuits designed upon present day principles. 0 l Y.

Considered .from a broad` aspect, our invention is predicated upon our discovery that itis practical to utilize, in appropriate circuits, a conductive interlinkage of` output and input circuits to effect regenerative amplification and/or detection.

l Our invention resides further in the positive control of the degree of regeneration obtained by this method of coupling. z .Inaccordance with. our inventionwehave provided methods and means for effecting regenerative amplication based upon conductive coupling rather than inductive or capacitive coupling, as commonly used in the thermionic art. The conductive coupling between circuits `utilized in our invention is preferably internal coupling, that is, we may utilize the coupling between circuits resulting from the conductive interlinkage of output and input electrodesv inherent inV gaseous discharge devices.

Certain objects and principles of our invention will be apparent, and the invention will be more readily understood by reference to the accompanying drawing, in which certain particular preferred forms of the invention are shown by way of illustration, but without limiting the invention thereto.

Fig. 1 sho-ws a radio receiver embodying my invention.

Fig. 2 is a graph of a discharge device operable with, or without, the grid battery of Fig. 1.

Fig. 3 is a graph of a Heany-I-Iaffcke gas cell of a type operable at a small positive bias. y Fig. 4 is a second embodiment of ourV invention and discloses means for controlling regeneration obtainable. with our circuit arrangement.`

Figs. land 4 omit illustrations of other stages, and the couplings between stages, the omission being in the interest of simplicity, it being understood the invention is applicable to hook-ups having any desired number of stages. Our invention is intended for use not only in radio circuits, as shown in Fig. 1, but is equally applicable to telephone and telegraph relayfcircuits, as well as to icertaini'ridustrial uses. j

'Referring now in detail to Fig. I, an antenna l is connected to a ground conductor 2, through a `coupling transformer 3, having a primary winding 4, anda secondary winding. The terminals of secondary winding, which are shunted by a ,tuning condenser 6,' are connected respectively to the electrodes 'l'anda of a `gaseous cell 9. 'The cell or tube 9 comprises an anode I 0 and a cathode element Il, in additiontojthe input electrodes 1 and 8. A single energizingsource is here designated simply by positive pole -l- 'and negative poley The necessary groundconnection, which may be through the transformer of a power pack, or through the coils thereof, is shown symbolically by the broken lines.` A ballast resistor I2 serves to limit the maximum amount of direct current permitted to lpass throughfthe tube. In `the tube here-shown either or both cathode Il and anode I0 may be output electrodes, as will hereinafter more fully appear. In any event, gas

in the tube aords an internal conductive path between all of the electrodes, and it is to be understood that We contemplate the use of tubes or cells of any suitable type wherein there is a conductive path between input and output electrodes. The output coupling from one stage to the next stage may beat any suitable point. It is entirely practical, for instance, to take the output I3 from across the terminal of ballast resistor I2, in which case one leg of the connection should include a condenser I4. A variable non-'inductive poten-'- tiometer I5 is connected across batteryI'B in the input circuit.

The tube 9 is preferably a Heany-I-Iaffcke gas cell of either the internal 'cathode type disclosed in co-pending application, Serial No. 542,304, or of external cathode typefrasV here shown, and as disclosed in co-pending applica` tion, Serial No. 548,410. v Theconstruction and operation of the I-Ieany Haifckefgas cell, asdisclosedl in the applications abovey cited, may be here briefly described as follows: two electrode elements, for instance, elements 8 and I'I of the present Fig. l, constitute the working cathode of the cell, that is', these electrodes may be considered as exciters of apparent electronic emission, the gas in the containerbeing the lprime source of electrons. One of these electrode elements, for instance element 8,.is positive to the cathode element II, and is negative tothe anode II). This electrode 8, be-

` cause of its dual relationship, is designated cathanode The anode II! is similar in function tothe plate in a thermionic tube, at least it serves to accelerate electrons towards itself, and may be considered as one of the output electrodes. The control electrode or grid is 'I.

yThe position and arrangement of gridV 'I and battery I6 are analogous to that of the grid and grid battery in circuits employing thermionic tubes. Our arrangement shown in Fig. 1, should not be confused with so called biasing arrangements, known in the art, which are all directed to maintaining the grid at such a negative potential relative t'o the cathode that substantially no currentA will 'flow in the input circuit. In accordance with our arrangement the grid may carry a large percentage of the anode or plate current, and, were it possible to offset by biasing =or otherwise this grid current, the tube would be unoperable for our present purpose.

lThe battery IB is not, therefor, arranged to prevent current iiowing in the grid circuit (in some cases battery I6 actually adds current to the circuit) but vserves rather to position the working point of'the cell on the proper section "offthe'grid voltage-plate current curve,-all of which will more `fully appear in connection with Figs. 2 and 3. The non-inductive potentiometer or variable resist-or I5 serves to control the interaction between theconductively coupled output and. input circuits, and hence the effective degree of. regeneration, by varying the resistivity or conductivity of the conductive coupling.

"Fig. 2 shows a plate current-grid voltage curve otagas cell. .In-the graph of the particular cell here shown it will be apparent to those skilled in the art that the device may be Worked at point C, lzero bias, and, therefore, Without a battery, or at approximately 15fto20 volts positive bias, in which case either a battery of that value or an equivalent resistor in the plate circuit is necessary to the working point. Since it will bev recalled Ythat amplification depends upon steepness rather than the height of the platecurrent grid voltage curve, and that it appears that hump A approximates hump B in steepness, it is obvious that our system for controlling regeneration is independent of so called biasing arrangements, as it is operable Without anyfbias,A if so desired.

Fig. 3 is a graph of a Heany-Haficke gas cell of vthe external cathode type. The graph is plotted to plate current as ordinates and grid V'voltage as abseissae--the calibration in milliam- 'peres and volts respectively. The working point C, on the plate current-grid voltage curve isl preferably at approximately .2 volts positive. With this particular tube We may include in our circuit the grid battery described in connection with Fig. l, it being understood from what has goneY before that While for gas tubes having certain characteristics we may employ a biasing battery, or its equivalent, it is not always necessary 'tli'at we do so.

`In Fig. 4 2D is the secondary Aof an input circuit transformer,` 2| a tuning condenser; the circuit 2li-2i constitutes the tuned circuit, to which the feed-back from plate 25 is directed. The conductive path from plate Y25 to tuned circuit 2li-2l is through the gas, which has been rendered conductiv'e by ionization, to grid 22 and thro-ugh the grid lead to circuit 2te-2i. The cell -24 here illustrated 'may be an internal cathode gas dis'- charge device of the type previously described, in which case cathode and cathanode 23 coin prise the ionizing circuit; electrodes 22 and 23, corresponding to electrodes 'I and 8 in Fig. 1, are terminals yfor the input circuit.

The output coupling may be in the plate or anode circuit, and is diagraminatically represented at 26. The maximum amount of direct current permitted to. pass' through the tube from the single source of supply (represented by posi'- tive and negative symbols) is limited by ballast resistor ITI. In the embodiment here shown the grid biasing battery is designated 2'9 and it may be utilized, if necessary or desirable, to x the vvo-rlA ing point on the grid voltage-plate current curve.

Instead of the potentiometer in the grid lead as described in connection With Fig. l, we may have the regeneration control directly in the tuned lcircuit 2li-2l. Thus, Aa variable connection -3is in electrical association with secondary 2e and ground 3l through condenser 32 and variable 'resistor 33. By proper adjustment of variables 3G and 33 any desired value 'or amount of current may be reimpressed on tuned input circuit 2li-2|. Y l

One very real advantage of utilizing the cori ductive connection made practical by our invenv tion, and one which will be obvious to those skilled in the art, is this: regeneration is independent of frequency. In present noneregenerative circuits employing inductive or capacitive feed'eb'ack the tickleror other control must be varied for dilf ferent frequencies; with our invention the con'- trols may be set for any desired value, and need not be changed regardless of the frequency vof the incoming signal.

lAs' many further mo'di'cations and `changesin details will suggest themselves to those skilled' in the art, Without departing from the spirit and scope of our invention, it is to bev understood' that the foregoing is' to be ini-.erpreted as illustrative, and Vnot in a limiting sense, except as required by the appended claims, and by the prior art.

What is claimed is:

1..- AA regenerative Asystem comprising cathanode,

cathode grid and anode electrodes immersed in a conductive gaseous medium, input and output circuits for said electrodes, said input circuit comprising a conductive connection from the grid to the cathanode, and said output circuit comprising a conductive connection from the anode to the cathode whereby energy in the output circuit is fed back conductively through the gas filling to the input circuit, and means to provide a positive control for varying the amount of regeneration.

2. A regenerative system comprising cathanode, cathode grid and anode electrodes immersed in rist conductive gaseous medium, input and output circuits for said electrodes, said input circuit comprising a conductive connection from the grid to the cathanode, and said output circuit comprising a conductive connection from the anode to the cathode, whereby energy in the output circuit is fed back conductively through the gas lling to the input circuit, and means connected to the input circuit to provide a positive control for varying the amount of regeneration.

3. A regenerative system comprising a gas lled electric discharge device having on the interior thereof input and output electrodes, an input circuit conductively connecting the input electrodes together exteriorly of the device, an output circuit conductively connecting the output electrodes together exteriorly of the device, and variable means in said input circuit to provide a positive control over the amount of regeneration.

4. A system according to claim 3 in which means for controlling the regeneration is serially connected in the input circuit.

5. A regenerative system comprising an electric discharge device having a gas lling, input and output electrodes Within said device, input and output circuits conductively connecting said electrodes together externally of the device, and a variable impedance in the input circuit for positively controlling the amount of energy fed back from the output circuit to the input circuit.

6. A system according to claim 5, in which the said impedance comprises substantially entirely a resistance.

7. A regenerative systemy comprising a gas lled electric discharge device, a cathode, a cath-anode, control grid and anode within said device, atuned input circuit connected across the cathanode and grid, an output circuit connecting the anode and cathode and means in said input circuit for controlling the amount of energy fed back thereto from the output circuit due to the gas filling.

8. A system according to claim 7 in which -the means for controlling the amount of energy fed back comprises a. variable impedance connecting the tuned circuit to ground.

9. A regenerative system comprising a gas iilled electric discharge device, cathode, cathanode, control grid and anode electrodes within said device, a tuned input circuit connected across the cathanode and control grid, an output circuit connected'across the cathode and anode, and a potentiometer arrangement in said tuned circuit for controlling the amount of regeneration and for biasing the grid to the proper point of the grid voltage-plate current characteristic.

10. A regenerative` system comprising a gas lled electric discharge device, cathode, cathanode, control grid and anode electrodes Within said device, a tuned input circuit connected across the grid and cathanode, an output circuit connected across the cathode and anode, a source of steady potential connected across the cathode and ano-de, and a regeneration control path comprising a variable impedance connection from a point in the tuned circuit to one terminal of said source of potential.

11. A regenerative system comprising a gas iilled electric discharge device, cathode, cathanode, control grid and anode electrodes within said device, a tuned input circuit connected across the control grid and cathanode, an output circuit including a source of steady working potential connected across the cathode and anode, a regeneration control path having one end connected to a terminal of said source of potential,

, the other end being adjustably connected to the said tuned circuit and including a variableresistance.

12. A regenerative system comprising a gas filled electric discharge device, cathode, cathanode, control grid and anode electrodes within said device, a tuning inductance having one terminal connected to the cathanode, a circuit including a source of steady working potential connected across the cathode and anode, and a variable impedance connection extending from a point intermediate the ends of the inductance to one terminal of said source of potential for controlling the amount of regeneration.

JOHN ALLEN HEANY. HERBERT ST. LAURENT. 

